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Untersuchung lasererzeugter Plasmen/Röntgenlaser

English title Investigation of laser-produced plasmas/X-ray lasers
Applicant Balmer Jürg E.
Number 132690
Funding scheme Project funding (Div. I-III)
Research institution Institut für angewandte Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Other disciplines of Physics
Start/End 01.10.2010 - 30.09.2012
Approved amount 550'600.15
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Keywords (10)

high-peak power lasers; X-ray lasers; laser-produced plasmas; chirped-pulse amplification; high-peak-power lasers; CPA lasers; EUV lasers; grazing-incidence pumping; collisional excitation; high-power lasers

Lay Summary (English)

Lead
Lay summary
Lasers in the extreme ultraviolet (EUV) and soft-x-ray wavelength range (0.2-30 nm) are expected to have an impact on applications as revolutionary as they did in the visible and infrared (IR) wavelength range. The range of these applications is wide as a result of the inherent properties of x-ray lasers: very high brilliance, short pulse duration, coherence, and short wavelength. The development of lasers in the x-ray spectral region is hence of fundamental importance in many fields such as microscopy, interferometry, x-ray lithography, surface analysis, photoelectron spectroscopy, atomic physics, and plasma physics. Most of the soft-x-ray lasers demonstrated experimentally up to now have used a hot, dense plasma produced by high-power visible or near-IR laser, in which a population inversion (the prerequisite for lasing action) is created by electron-collisional excitation. In the past, the high pump energy required for saturated lasing output has restricted the development of x-ray lasers to a few large-scale laser facilities around the world. Reduction of the pump energy by exploiting novel pumping schemes remains the primary goal in plasma x-ray laser research if these are to become a standard laboratory tool. Recent progress using the technique of grazing-incidence pumping (GRIP) has lead to saturated x?ray lasing in plasmas of Ni-like Ag, Pd, Sn, Sb, and Te at wavelengths down to 10.9 nm, some at repetition rates of up to 10 Hz, and for pump energies as low as 2 J. Simulations predict that sub-10-nm lasing should be feasible with 5-10 J of pump energy, and ~100 J would be required to generate an x-ray laser close to the water window (2.5-4.4 nm). The primary goal of this project is to extend the range of saturated lasing to wavelengths below 10 nm by exploiting and optimizing the GRIP scheme in plasmas produced from targets of Ba, La, Sm, etc., all elements of the lanthanide (rare-earth) group. To this end, new target fabrication techniques and/or the use of compound targets, e.g., barium fluoride and lanthanum fluoride, will be investigated. The second goal will be the construction of the compact (table-top) 2-J, few-Hz, Nd:YLF laser system based on optical parametric chirped-pulse amplification (OPCPA). The higher repetition rate is imperative, if applications such as x-ray lithography and photoelectron spectroscopy are envisaged.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Extreme ultraviolet lasers: principles and potential for next-generation lithography
Balmer Juerg E., Bleiner Davide, Staub Felix (2012), Extreme ultraviolet lasers: principles and potential for next-generation lithography, in JOURNAL OF MICRO-NANOLITHOGRAPHY MEMS AND MOEMS, 11(2), 021119-1-021119-4.
Soft-x-ray lasing in nickel-like barium at 9.2 nm using the grazing-incidence scheme
Staub F., Imesch C. (2012), Soft-x-ray lasing in nickel-like barium at 9.2 nm using the grazing-incidence scheme, in Optics Communications, 285, 2118-2121.
Line focusing for soft x-ray laser-plasma lasing
Bleiner Davide, Balmer Jürg E., Staub Felix, Ekinci Yasin, Balmer Juerg (2011), Line focusing for soft x-ray laser-plasma lasing, in Applied Optics , 50(36), 6689-6696.
Gain-saturated Ni-like antimony laser at 11.4 nm in grazing-incidence pumping geometry
Imesch C., Staub F., Feurer Thomas, Balmer Jürg (2010), Gain-saturated Ni-like antimony laser at 11.4 nm in grazing-incidence pumping geometry, in Optics Communications, 283, 66-70.

Associated projects

Number Title Start Funding scheme
121627 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2008 Project funding (Div. I-III)
121627 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2008 Project funding (Div. I-III)
144380 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2012 Project funding (Div. I-III)
144380 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2012 Project funding (Div. I-III)

Abstract

Lasers in the soft-x-ray wavelength range (0.3    30 nm) are expected to have an impact on applica-tions as revolutionary as they did in the visible and infrared wavelength range. The range of these applications is very wide as a result of the inherent properties of x-ray lasers: high brilliance, short pulse duration, coherence, and short wavelength. The development of lasers in the x-ray spec-tral region is hence of fundamental importance in many fields such as holo-graphy, microscopy, interferome-try, x-ray lithography, surface analysis, atomic physics, and plasma physics.
Most of the soft-x-ray lasers demonstrated experimen-tally up to now have used the electron-collisio-nal excitation scheme in a hot, dense laser-produced plasma. Reducing the very high pump energy required for saturated output remains the primary goal in x-ray laser research if these are to become a stan-dard laboratory tool. Using the novel technique of grazing-inci-dence pumping (GRIP), saturated x-ray lasing has recently been demonstrated in plasmas of Ni-like Ag, Pd, and Sn at wavelengths down to 11.9 nm, at repetition rates of up to 10 Hz, and for pump energies as low as 1 J. Simula-tions predict that sub-10-nm lasing should be feasible with 5-10 J of pump energy, and ~100 J would be required to generate an x-ray laser close to the water window (2.5-4.4 nm).
The main goals of the current project are to: i) use the existing CPA laser system to systematically investigate and optimize sub-10-nm x-ray lasing in the grazing-incidence pump-ing(GRIP) geometry, and ii) complete the construction of the compact, 2-J, few-Hz repetition rate, OPCPA/Nd:YLF laser system.
The recent completion of the CPA upgrade of the laser system has resulted in pulse peak powers of up to 10 TW (20 J/2 ps) available for x-ray laser experiments. The main effort will be devoted to the systematic optimization of the travelling-wave excitation (TWE) scheme for x-ray lasing in targets of Ba, La, and Ce at wavelengths of 9.2, 8.8, and 8.5 nm, respectively.
With the TWE scheme optimized, it should be feasible to extend the range of x-ray lasing wavelengths accessible to the GRIP scheme even further into the region below 10 nm. The main candidate for lasing in this region will be Sm at a wavelength of 7.3 nm, as it is the most stable among the rare-earth elements (La, Pr, Sm, Gd, Dy, etc..
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